"Doctor Who" returns to BBC America for the second half of Season 7 beginning March 30, and the new trailer previews wild adventures ahead for the Doctor (
Matt Smith) and mysterious new companion Clara (
Jenna-Louise Coleman).

"I look at you every single day and I don't understand a thing about you," the Doctor says about Clara in the trailer. Adding: "You're the impossible girl."

Coleman quietly made her debut in the Season 7 premiere, "Asylum of the Daleks," as Oswin Oswald -- a space traveler trapped inside a Dalek. She then returned as Clara in the annual Christmas special, "The Snowmen," as an 1890s governess who the Doctor opens up to after the
loss of previous companions Amy Pond and Rory Williams. But just after the Doctor invites her on to the TARDIS, Clara was killed.

The Christmas special closed out with a brief glimpse of the character destined to become the Doctor's actual companion. So even though we've met her twice, we really haven't met her at all. Or have we? It's all very timey-wimey, and a mystery that's sure to play out through these next eight episodes.